Removable bone plate



Patented Apr. 20, 1948 UNITED STATES PATENT OFFICE REMOVABLE BONE PLATE Chester H. Smith, Pittsburg, Kans. Application October 7, 1946, Serial No. 701,821

(Cl. 12S-92) 3 Claims.

The instant invention relates to what is believed to be a new method of utilizing a bone plate for purposes of setting and repairing a bone fracture and the particular plate and other attending accessories utilized in reducing the method to actual and reliable practice.

In respect to the method phases, I have evolved and pursue a unique and satisfactory technique which consists in exposing the bone and fracture by way of a customary incision under direct vision, applying the bone plate, anchoring same to bone in proper position through the medium of retention screws, exposing wrench ends, with which the screws are provided, through the outermost surfaces of the flesh for subsequent removal, and equipping the plate at one end with a hingedly mounted, laterally positioned lever, which lever is used to define a constantly open channel in the ilesh, and which also serves as pilot means for removing the main bone plate once the attaching screws are removed; this all accomplished without requiring, as is ordinarily the case, a second operation.

Interpreted from another point of view, the invention has to do with a structurally distinct and readily applicable and removable bone plate which is placed upon the bone by open operation. under direct vision, during which time the fragv ments and muscles, or anything that exists between the ends of the bone fragments, may be removed and the ends cleaned and the best apposition obtained, said plate being removed the next day or at any time withn four to sixteen weeks, this without requiring the customary second operation.

Novelty is predicated, on the one hand, on a bone plate longitudinally elongated and having apertures to accommodate anchoring screws, said bone plate having its longitudinal edges straight and said plate being curved slightly in a transverse direction for appropriate bone contacting results.

Additional novelty is predicated upon novel and improved anchoring screws, each screw comprising a shank having a screw threaded inner end, a shouldered portion adjacent said inner end, a smooth main shaft and said main shaft being reduced at its outer end and said reduced portion constituting an extension which is polygonal in cross-section to permit a wrench to be employed in iirst tightening and later removing and extracting the screws.

Furthermore, and as before implied, novelty is predicated upon a detachable screw equipped bone plate having means at one end whereby a pilot lever or equivalent member is separably and hingedly Vattached to said one end of the plate, this arrangement permitting the lever to be properly angled to form the aforementioned channel through which the lever and plate may be withdrawn, this without requiring a further incision or secondary operation.

Other objects, features and advantages will become more readily apparent from the following description and the accompanying illustrative drawings.

In the drawings wherein like numerals are employed to designate like parts throughout the views:

Figure 1 is a top plan view of a lever equipped bone plate constructed in accordance with th'e principles of this invention showing the assembly of anchoring screws.

Figure 2 is an edge elevational view with the screws removed.

Figure 3 is a cross-section through the bone plate, this on the line 3 3 of Figure 2, looking in the direction of the arrows.

Figure 4 is a detail view of one of the screws.

Figure 5 is a perspective View of the wrench or/ other tool used for removing the screws one by one, and

Figure 6 is a fragmentary sectional elevational view showing a human leg, the fractured bone, the'bone plate, the anchoring screws and the preferred withdrawal means, lever attached to the plate. Y

Referring now to Figure 6, the human leg is herein denoted by the numeral 8, the bone sections by the numerals 9 and Ill, the fracture at I I, and th'e flesh, or leg proper, at I2,

Referring now to the appliance or means under consideration, this comprises a longitudinally elongated plate, commonly referred to in the trade as a bone plate, I3. It is provided in the instant situation, with longitudinally spaced holes for anchoring screws, said screws being generally denoted by the numerals Ill. The plate I3 is transversely curved as indicated in Figure 3 and provided at one end with a hook I5. The hook serves to accommodate the slotted end portion I6 of the withdrawal or plate removal lever I1. This part I'l is of th'e same width as the plate and also of the same cross-sectional dimension. The outer end is bevelled as indicated at I8. The slot and hook arrangement provides the necessary separable and hinging connection between the plate and lever.

As before mentioned, the anchoring screw comprises an elongated shank I 9 cylindrical in crosssection and having an enlarged inner end portion 20 which is .fashioned into a stop shoulder and which sh'oulder is engageable with the outer surface of the plate when said plate is applied as seen in Figure 6. The screw threaded portion beyond the shoulder is denoted at 2| :and constitutes the means for tapping the screw into the bone sections 9 and IIJ as shown in Figure 6. The free end of the screw is tapered and bifurcated and the furcations 22 facilitate the screw action. The outer end of th'e shank is reduced as at 23 and is polygonal in cross-section to provide a tool element, this to accommodate the socket portion of the wrench 24.

At this stage, I desire to direct attention to two salient points having to do with the method and -appliance phases of the invention, to wit:

1. A bone plate that is placed upon the bone by open operation under direct vision. Bone fragments and muscle or anything thatis between ends oi bone fragments can be removed and ends cleaned and best apposition obtained` Plate is applied, wound closed and cast applied. Bone plate may then be removed the next day or four to sixteen weeks. Plate may be removed without secondary operation.-

2. All that is necessary is that when plate is to be removed, the screws are removed and exe tension bar is rocked to loosen plate from bone callous and with a slight pull plate is removed. This is all done if desi-red, in the patients room or any place that the doctor wishes to remove bone plate, no secondary operation necessary; and no metal bone plate is left on the bone which may require open operation later. .This bone plate has all the advantages of being placed on the bone, screwed down tight, which holds bone in place, requiring no other operating equipment than the ordinary surgeon has in his case. No chance of leaving anything between ends of bone, thereby, getting non-union. No uoroscopy dur--4 ing the operation which is a protection from X ray burn..

In addition to the above, I`feel disposed to emphasize and to stress the following relevant face tors, to wit:

I claim the only bone plate that is placed directly on the bone under direct vision', screwed down tight with al1 the advantages of such a rigid Xad tion, plus, being removable without secondary operation. This is done by placing an interd changeable bar on the end of bone plate that is hinged at the plate, in such a manner, that any angle may be obtained and when plate is removed, the plate and extension bar straightens and cannot become disengaged. 'I'hisexte-n'sion bar is the same thick-ness and width as plates, thereby,y makes a channel for the plate to be ree moved to follow out.- The screws are different in design, in that they are streamlined with square ends; so that ya wrench may be applied for their insertion or removed and stuck out through incision of member just far enough to apply wrench for removal. They are also bevelled for additional shoulder strength. Plate also curved for additional strength. These plates will be made in many sizes as well as the extension bar and screws will be Various lengths and all are interchangeable, whereby, a short plate and long extension bar may be used or vice-versa or short plate and short bar for smaller bones. All screws with extension plates and extension bars with knife edge on end of extension bar for introduction are interchangeable.

Although the description and claims show the withdrawal means as having to do with a rigid piece 0f inetal hingedly connected with the plate and constituting the preferred ways and means of achieving the withdrawal step, I desire to bring forth the fact at this point that a iiexible spring steel tape may be used and attached at its inner end rigidly to the co-acting end of the plate. At any rate, this is an adaptation within the purview of the present invention, and although it is not shown, the claims have been worded to comprehend same. y

A careful consideration of the foregoing description in conjunction with the invention as illustrated in the drawings will enable the reader to obtain a clear understanding and impression of the alleged features of merit and novelty sufi-- cient to clarify lthe construction of the invention vas hereinafter claimed.

Minor changes in shape, size, materials and rearrangement of parts may be resorted to in actual practice so long as no departure is made from the invention as claimed.

I claim: l Y

I. In an 'appliance for treating bone fractures,

a bone plate, a lever, and means separably and4 hingedly connecting the inner end with one end of said plate.

2. In an appliance for treating, bone fractures, a bone plate, a lever, and means separably and hingedly connecting the inner end of vthe lever with one end of said plate, comprising a hook on the plate and a slot in the lever. 1

3. In a structural fracture treating and repair appliance of the class described, a bone plate lon.- gitudinally elongated, transversely bowed and having rectilinearly straight longitudinal edges, said bone plate being provided at one end with a hook to accommodate the slotted end oi a plate loosening andv withdrawing lever.V

of thel lever sMrrH.,

REFERENCES CITED The following references are of record iin the file oi this patent:

UITED STATES PATENTS Number Name Date 1,960,892 Boever May 20, 1934. 2,024,325 Allen Dec. 17, 1935 2,1Ii`359 Hawley i Oct. 18, 1938 2,388,482 Haynes Nov. 6, 1945 

